Anatomical features of first maxillary premolars may greatly affect endodontic and following restorative treatments. The aim of this study was to evaluate root canal configuration and root wall thickness of first maxillary premolars using a preexisting CBCT database. A CBCT database of 400 first maxillary premolar was used to study canal configuration, presence of furcation-facing groove on the buccal root and root wall thickness. Root wall thickness was measured from axial CBCT slices at three critical points of the root: The most coronal part of the furcation-facing groove in the buccal root, when present, the CEJ level of the palatal root and 5 mm apically to the CEJ level of the palatal root. Vertucci Type IV configuration was the most common among all teeth, but in single-rooted teeth, Vertucci Type II was predominant. The mean thickness of the buccal root in the area of a furcation-facing groove was 1.1 (±0.2) mm, but in 39% of the cases, it was thinner than 1 mm. The mean thickness of the palatal root at 5 mm from the CEJ was 1.1 (±0.2), but in 28% of the cases, it was thinner than 1 mm. Thickness of root dentin walls of first maxillary premolars varies and may be limited at critical points in both buccal and palatal roots. In case the patient has a previous CBCT scan it may be useful for planning treatment of first maxillary premolars, in order to recognize and avoid potential risks such as furcation-facing groove, thin dentin walls in critical areas and presence of Type II Verucci canal, all of which may dictate less invasive procedures, using smaller files.